Better comment

IPython/nbconvert/filters/latex.py

@@ -1,124 +1,124 b''
 """Latex filters.
 
 Module of useful filters for processing Latex within Jinja latex templates.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 import re
 
 #-----------------------------------------------------------------------------
 # Globals and constants
 #-----------------------------------------------------------------------------
 
 LATEX_RE_SUBS = (
     (re.compile('\033\[[0-9;]+m'), ''),  # handle console escapes
     (re.compile(r'\.\.\.+'), r'\\ldots'),
 )
 
 # Latex substitutions for escaping latex.
 # see: http://stackoverflow.com/questions/16259923/how-can-i-escape-latex-special-characters-inside-django-templates
 
 LATEX_SUBS = {
     '&':  r'\&',
     '%':  r'\%',
     '$':  r'\$',
     '#':  r'\#',
     '_':  r'\_',
     '{':  r'\{',
     '}':  r'\}',
     '~':  r'\textasciitilde{}',
     '^':  r'\^{}',
     '\\': r'\textbackslash{}',
 }
 
 
 #-----------------------------------------------------------------------------
 # Functions
 #-----------------------------------------------------------------------------
 
 __all__ = ['escape_latex',
            'strip_math_space']
 
 def escape_latex(text):
     """
-    Escape characters that may conflict with latex.
+    Remove ansi codes and escape characters that may conflict with latex.
 
     Parameters
     ----------
     text : str
         Text containing characters that may conflict with Latex
     """
     text = ''.join([LATEX_SUBS.get(c, c) for c in text])
     for pattern, replacement in LATEX_RE_SUBS:
         text = pattern.sub(replacement, text)
 
     return text
     
     
 def strip_math_space(text):
     """
     Remove the space between latex math commands and enclosing $ symbols.
     This filter is important because latex isn't as flexible as the notebook
     front end when it comes to flagging math using ampersand symbols.
     
     Parameters
     ----------
     text : str
         Text to filter.
     """
 
     # First, scan through the markdown looking for $.  If
     # a $ symbol is found, without a preceding \, assume
     # it is the start of a math block.  UNLESS that $ is
     # not followed by another within two math_lines.
     math_regions = []
     math_lines = 0
     within_math = False
     math_start_index = 0
     ptext = ''
     last_character = ""
     skip = False
     for index, char in enumerate(text):
 
         #Make sure the character isn't preceeded by a backslash
         if (char == "$" and last_character != "\\"):
 
             # Close the math region if this is an ending $
             if within_math:
                 within_math = False
                 skip = True
                 ptext = ptext+'$'+text[math_start_index+1:index].strip()+'$'
                 math_regions.append([math_start_index, index+1])
             else:
 
                 # Start a new math region
                 within_math = True
                 math_start_index = index
                 math_lines = 0
 
         # If we are in a math region, count the number of lines parsed.
         # Cancel the math region if we find two line breaks!
         elif char == "\n":
             if within_math:
                 math_lines += 1
                 if math_lines > 1:
                     within_math = False
                     ptext = ptext+text[math_start_index:index]
 
         # Remember the last character so we can easily watch
         # for backslashes
         last_character = char
         if not within_math and not skip:
             ptext = ptext+char
         if skip:
             skip = False
     return ptext